As one of image display apparatuses, there is known a liquid crystal display apparatus. Along with the technological innovations including wide viewing angle, high definition, high-speed response, and color reproducibility of the liquid crystal display apparatus, the application of the liquid crystal display apparatus has also been spread from a laptop computer and a monitor to a television, a mobile telephone, and further to a personal digital assistant (PDA). According to a basic configuration, the liquid crystal display apparatus includes a liquid crystal cell in which a pair of glass substrates each having a transparent electrode are opposed to each other with a predetermined interval via spacers and a liquid crystal material is sealed between the glass substrates, and polarizing plates arranged on both sides of the liquid crystal cell.
For example, in middle and small-sized liquid crystal display apparatuses used in the mobile telephones and the PDAs, a semi-transmissive reflection-type liquid crystal display apparatus has been proposed in addition to a transmission-type liquid crystal display apparatus and a reflection-type liquid crystal display apparatus (for example, see Patent Documents 1 and 2). The semi-transmissive reflection-type liquid crystal display apparatus uses ambient light in a bright place in the same way as in the reflection-type liquid crystal display apparatus, and enables a display to be recognized visually with an internal light source such as a backlight in a dark place. In other words, the semi-transmissive reflection-type liquid crystal display apparatus adopts a display system having both a reflection type and a transmission type, and can switch between a reflection mode and a transmission mode depending upon the lightness of the environment. As a result, the semi-transmissive reflection-type liquid crystal display apparatus can perform a clear display even in a dark environment while reducing power consumption, so it is preferably used in a display part of mobile equipment.
A specific example of the semi-transmissive reflection-type liquid crystal display apparatus described above includes a liquid crystal display apparatus, for example, in which a reflective film obtained by forming a window portion for light transmittance in a metal film such as aluminum is provided on an inner side of a lower substrate, and the reflective film is allowed to function as a semi-transmissive reflective plate. In the liquid crystal display apparatus described above, in a reflection mode, outer light incident from an upper substrate side passes through the liquid crystal layer, is reflected from the reflective film on the inner side of the lower substrate, passes through the liquid crystal layer again, and is outgoing from the upper substrate side, thereby contributing to a display. On the other hand, in a transmission mode, light of a backlight incident from the lower substrate side passes through the window portion of the reflective film, passes through the liquid crystal layer, and is outgoing from the upper substrate side, thereby contributing to a display. Thus, in a reflective film formation region, an area where the window portion is formed functions as a transmission display region, and the other area functions as a reflection display region.
On the other hand, the liquid crystal display apparatus uses an optical film made of various polymer materials as an optical compensation layer for the purpose of enhancing image quality, as well as a polarizing plate. The optical compensation layer is selected appropriately based on the display mode (TN, VA, OCB, IPS, ECB, etc.) of liquid crystal. As such an optical compensation layer, for example, a uniaxially stretched film of a polymer film is known.
In the above-mentioned conventional liquid crystal display apparatus, a cover plate made of glass (thickness: about 0.5 mm) or a thick plastic sheet is provided on an outer side of a polarizing plate to prevent the damage of the polarizing plate. However, in middle and small-sized liquid crystal display apparatuses required to be reduced in thickness and weight, it is not preferred to provide such a cover plate. Further, it can be assumed that the middle and small-sized liquid crystal display apparatuses are used under severe conditions (for example, high temperature and high humidity), so moist heat resistance is also required.
Patent Document 1: JP 11-242226 A
Patent Document 2: JP 2001-209065 A